src/credential/gnunet-service-credential.c

   1 /*
   2      This file is part of GNUnet.
   3      Copyright (C) 2011-2013 GNUnet e.V.
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18      Boston, MA 02110-1301, USA.
  19 */
  20 /**
  21  * @file gns/gnunet-service-credential.c
  22  * @brief GNU Credential Service (main service)
  23  * @author Adnan Husain
  24  */
  25 #include "platform.h"
  26 #include "gnunet_util_lib.h"
  27 #include "gnunet_credential_service.h"
  28 #include "gnunet_statistics_service.h"
  29 #include "credential.h"
  30 #include "credential_serialization.h"
  31 #include "gnunet_protocols.h"
  32 #include "gnunet_signatures.h"
  33
  34 #include <gnunet_dnsparser_lib.h>
  35 #include <gnunet_identity_service.h>
  36 #include <gnunet_gnsrecord_lib.h>
  37 #include <gnunet_namestore_service.h>
  38 #include <gnunet_gns_service.h>
  39
  40
  41 #define GNUNET_CREDENTIAL_MAX_LENGTH 255
  42
  43 struct VerifyRequestHandle;
  44
  45 struct DelegationSetQueueEntry;
  46
  47
  48 struct DelegationChainEntry
  49 {
  50   /**
  51    * DLL
  52    */
  53   struct DelegationChainEntry *next;
  54
  55   /**
  56    * DLL
  57    */
  58   struct DelegationChainEntry *prev;
  59
  60   /**
  61    * The issuer
  62    */
  63   struct GNUNET_CRYPTO_EcdsaPublicKey issuer_key;
  64
  65   /**
  66    * The subject
  67    */
  68   struct GNUNET_CRYPTO_EcdsaPublicKey subject_key;
  69
  70   /**
  71    * The issued attribute
  72    */
  73   char *issuer_attribute;
  74
  75   /**
  76    * The delegated attribute
  77    */
  78   char *subject_attribute;
  79 };
  80
  81 /**
  82  * DLL for record
  83  */
  84 struct CredentialRecordEntry
  85 {
  86   /**
  87    * DLL
  88    */
  89   struct CredentialRecordEntry *next;
  90
  91   /**
  92    * DLL
  93    */
  94   struct CredentialRecordEntry *prev;
  95
  96
  97   /**
  98    * Payload
  99    */
 100   struct GNUNET_CREDENTIAL_Credential *credential;
 101 };
 102
 103 /**
 104  * DLL used for delegations
 105  * Used for OR delegations
 106  */
 107 struct DelegationQueueEntry
 108 {
 109   /**
 110    * DLL
 111    */
 112   struct DelegationQueueEntry *next;
 113
 114   /**
 115    * DLL
 116    */
 117   struct DelegationQueueEntry *prev;
 118
 119   /**
 120    * Sets under this Queue
 121    */
 122   struct DelegationSetQueueEntry *set_entries_head;
 123
 124   /**
 125    * Sets under this Queue
 126    */
 127   struct DelegationSetQueueEntry *set_entries_tail;
 128
 129   /**
 130    * Parent set
 131    */
 132   struct DelegationSetQueueEntry *parent_set;
 133
 134   /**
 135    * Required solutions
 136    */
 137   uint32_t required_solutions;
 138 };
 139
 140 /**
 141  * DLL for delegation sets
 142  * Used for AND delegation set
 143  */
 144 struct DelegationSetQueueEntry
 145 {
 146   /**
 147    * DLL
 148    */
 149   struct DelegationSetQueueEntry *next;
 150
 151   /**
 152    * DLL
 153    */
 154   struct DelegationSetQueueEntry *prev;
 155
 156     /**
 157    * GNS handle
 158    */
 159   struct GNUNET_GNS_LookupRequest *lookup_request;
 160
 161   /**
 162    * Verify handle
 163    */
 164   struct VerifyRequestHandle *handle;
 165
 166   /**
 167    * Parent attribute delegation
 168    */
 169   struct DelegationQueueEntry *parent;
 170
 171   /**
 172    * Issuer key
 173    */
 174   struct GNUNET_CRYPTO_EcdsaPublicKey *issuer_key;
 175
 176   /**
 177    * Queue entries of this set
 178    */
 179   struct DelegationQueueEntry *queue_entries_head;
 180
 181   /**
 182    * Queue entries of this set
 183    */
 184   struct DelegationQueueEntry *queue_entries_tail;
 185
 186   /**
 187    * Parent QueueEntry
 188    */
 189   struct DelegationQueueEntry *parent_queue_entry;
 190
 191   /**
 192    * Issuer attribute delegated to
 193    */
 194   char *issuer_attribute;
 195
 196   /**
 197    * The current attribute to look up
 198    */
 199   char *lookup_attribute;
 200
 201   /**
 202    * Trailing attribute context
 203    */
 204   char *attr_trailer;
 205
 206   /**
 207    * Still to resolve delegation as string
 208    */
 209   char *unresolved_attribute_delegation;
 210
 211   /**
 212    * The delegation chain entry
 213    */
 214   struct DelegationChainEntry *delegation_chain_entry;
 215
 216 };
 217
 218
 219 /**
 220  * Handle to a lookup operation from api
 221  */
 222 struct VerifyRequestHandle
 223 {
 224
 225   /**
 226    * We keep these in a DLL.
 227    */
 228   struct VerifyRequestHandle *next;
 229
 230   /**
 231    * We keep these in a DLL.
 232    */
 233   struct VerifyRequestHandle *prev;
 234
 235   /**
 236    * Handle to the requesting client
 237    */
 238   struct GNUNET_SERVICE_Client *client;
 239
 240   /**
 241    * GNS handle
 242    */
 243   struct GNUNET_GNS_LookupRequest *lookup_request;
 244
 245   /**
 246    * Size of delegation tree
 247    */
 248   uint32_t delegation_chain_size;
 249
 250   /**
 251    * Children of this attribute
 252    */
 253   struct DelegationChainEntry *delegation_chain_head;
 254
 255   /**
 256    * Children of this attribute
 257    */
 258   struct DelegationChainEntry *delegation_chain_tail;
 259
 260   /**
 261    * Issuer public key
 262    */
 263   struct GNUNET_CRYPTO_EcdsaPublicKey issuer_key;
 264
 265   /**
 266    * Issuer attribute
 267    */
 268   char *issuer_attribute;
 269
 270   /**
 271    * Subject public key
 272    */
 273   struct GNUNET_CRYPTO_EcdsaPublicKey subject_key;
 274
 275   /**
 276    * Credential DLL
 277    */
 278   struct CredentialRecordEntry *cred_chain_head;
 279
 280   /**
 281    * Credential DLL
 282    */
 283   struct CredentialRecordEntry *cred_chain_tail;
 284
 285   /**
 286    * Credential DLL size
 287    */
 288   uint32_t cred_chain_size;
 289
 290   /**
 291    * Root Delegation Set
 292    */
 293   struct DelegationSetQueueEntry *root_set;
 294
 295   /**
 296    * Current Delegation Pointer
 297    */
 298   struct DelegationQueueEntry *current_delegation;
 299
 300   /**
 301    * request id
 302    */
 303   uint32_t request_id;
 304
 305   /**
 306    * Pending lookups
 307    */
 308   uint64_t pending_lookups;
 309
 310   /**
 311    * Credential iterator
 312    */
 313   struct GNUNET_NAMESTORE_ZoneIterator *cred_collection_iter;
 314
 315   /**
 316    * Collect task
 317    */
 318   struct GNUNET_SCHEDULER_Task *collect_next_task;
 319
 320 };
 321
 322
 323 /**
 324  * Head of the DLL.
 325  */
 326 static struct VerifyRequestHandle *vrh_head;
 327
 328 /**
 329  * Tail of the DLL.
 330  */
 331 static struct VerifyRequestHandle *vrh_tail;
 332
 333 /**
 334  * Handle to the statistics service
 335  */
 336 static struct GNUNET_STATISTICS_Handle *statistics;
 337
 338 /**
 339  * Handle to GNS service.
 340  */
 341 static struct GNUNET_GNS_Handle *gns;
 342
 343
 344 /**
 345  * Handle to namestore service
 346  */
 347 static struct GNUNET_NAMESTORE_Handle *namestore;
 348
 349 static void
 350 cleanup_delegation_set (struct DelegationSetQueueEntry *ds_entry)
 351 {
 352   struct DelegationQueueEntry *dq_entry;
 353   struct DelegationSetQueueEntry *child;
 354
 355   if (NULL == ds_entry)
 356     return;
 357
 358   for (dq_entry = ds_entry->queue_entries_head;
 359        NULL != dq_entry;
 360        dq_entry = ds_entry->queue_entries_head)
 361   {
 362     GNUNET_CONTAINER_DLL_remove (ds_entry->queue_entries_head,
 363                                  ds_entry->queue_entries_tail,
 364                                  dq_entry);
 365     for (child = dq_entry->set_entries_head;
 366          NULL != child;
 367          child = dq_entry->set_entries_head)
 368     {
 369       GNUNET_CONTAINER_DLL_remove (dq_entry->set_entries_head,
 370                                    dq_entry->set_entries_tail,
 371                                    child);
 372       cleanup_delegation_set (child);
 373     }
 374     GNUNET_free (dq_entry);
 375   }
 376   if (NULL != ds_entry->issuer_key)
 377     GNUNET_free (ds_entry->issuer_key);
 378   if (NULL != ds_entry->lookup_attribute)
 379     GNUNET_free (ds_entry->lookup_attribute);
 380   if (NULL != ds_entry->issuer_attribute)
 381     GNUNET_free (ds_entry->issuer_attribute);
 382   if (NULL != ds_entry->unresolved_attribute_delegation)
 383     GNUNET_free (ds_entry->unresolved_attribute_delegation);
 384   if (NULL != ds_entry->attr_trailer)
 385     GNUNET_free (ds_entry->attr_trailer);
 386   if (NULL != ds_entry->lookup_request)
 387   {
 388     GNUNET_GNS_lookup_cancel (ds_entry->lookup_request);
 389     ds_entry->lookup_request = NULL;
 390   }
 391   if (NULL != ds_entry->delegation_chain_entry)
 392   {
 393     if (NULL != ds_entry->delegation_chain_entry->subject_attribute)
 394       GNUNET_free (ds_entry->delegation_chain_entry->subject_attribute);
 395     if (NULL != ds_entry->delegation_chain_entry->issuer_attribute)
 396       GNUNET_free (ds_entry->delegation_chain_entry->issuer_attribute);
 397     GNUNET_free (ds_entry->delegation_chain_entry);
 398   }
 399   GNUNET_free (ds_entry);
 400 }
 401
 402 static void
 403 cleanup_handle (struct VerifyRequestHandle *vrh)
 404 {
 405   struct CredentialRecordEntry *cr_entry;
 406   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 407               "Cleaning up...\n");
 408   if (NULL != vrh->lookup_request)
 409   {
 410     GNUNET_GNS_lookup_cancel (vrh->lookup_request);
 411     vrh->lookup_request = NULL;
 412   }
 413   cleanup_delegation_set (vrh->root_set);
 414   if (NULL != vrh->issuer_attribute)
 415     GNUNET_free (vrh->issuer_attribute);
 416   for (cr_entry = vrh->cred_chain_head;
 417        NULL != vrh->cred_chain_head;
 418        cr_entry = vrh->cred_chain_head)
 419   {
 420     GNUNET_CONTAINER_DLL_remove (vrh->cred_chain_head,
 421                                  vrh->cred_chain_tail,
 422                                  cr_entry);
 423     if (NULL != cr_entry->credential);
 424       GNUNET_free (cr_entry->credential);
 425     GNUNET_free (cr_entry);
 426   }
 427   GNUNET_free (vrh);
 428 }
 429
 430 /**
 431  * Task run during shutdown.
 432  *
 433  * @param cls unused
 434  * @param tc unused
 435  */
 436 static void
 437 shutdown_task (void *cls)
 438 {
 439   struct VerifyRequestHandle *vrh;
 440
 441   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 442               "Shutting down!\n");
 443
 444   while (NULL != (vrh = vrh_head))
 445   {
 446     //CREDENTIAL_resolver_lookup_cancel (clh->lookup);
 447     GNUNET_CONTAINER_DLL_remove (vrh_head,
 448                                  vrh_tail,
 449                                  vrh);
 450     cleanup_handle (vrh);
 451   }
 452
 453   if (NULL != gns)
 454   {
 455     GNUNET_GNS_disconnect (gns);
 456     gns = NULL;
 457   }
 458   if (NULL != namestore)
 459   {
 460     GNUNET_NAMESTORE_disconnect (namestore);
 461     namestore = NULL;
 462   }
 463   if (NULL != statistics)
 464   {
 465     GNUNET_STATISTICS_destroy (statistics,
 466                                GNUNET_NO);
 467     statistics = NULL;
 468   }
 469
 470 }
 471
 472
 473
 474 /**
 475  * Send.
 476  *
 477  * @param handle the handle to the request
 478  */
 479 static void
 480 send_lookup_response (struct VerifyRequestHandle *vrh)
 481 {
 482   struct GNUNET_MQ_Envelope *env;
 483   struct DelegationChainResultMessage *rmsg;
 484   struct DelegationChainEntry *dce;
 485   struct GNUNET_CREDENTIAL_Delegation dd[vrh->delegation_chain_size];
 486   struct GNUNET_CREDENTIAL_Credential cred[vrh->cred_chain_size];
 487   struct CredentialRecordEntry *cd;
 488   size_t size;
 489   int i;
 490
 491   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 492               "Sending response\n");
 493   dce = vrh->delegation_chain_head;
 494   for (i=0;i<vrh->delegation_chain_size;i++)
 495   {
 496     dd[i].issuer_key = dce->issuer_key;
 497     dd[i].subject_key = dce->subject_key;
 498     dd[i].issuer_attribute = dce->issuer_attribute;
 499     dd[i].issuer_attribute_len = strlen (dce->issuer_attribute)+1;
 500     dd[i].subject_attribute_len = 0;
 501     dd[i].subject_attribute = NULL;
 502     if (NULL != dce->subject_attribute)
 503     {
 504       dd[i].subject_attribute = dce->subject_attribute;
 505       dd[i].subject_attribute_len = strlen(dce->subject_attribute)+1;
 506     }
 507     dce = dce->next;
 508   }
 509
 510   /**
 511    * Get serialized record data
 512    * Append at the end of rmsg
 513    */
 514   cd = vrh->cred_chain_head;
 515   for (i=0;i<vrh->cred_chain_size;i++)
 516   {
 517     cred[i].issuer_key = cd->credential->issuer_key;
 518     cred[i].subject_key = cd->credential->subject_key;
 519     cred[i].issuer_attribute_len = strlen(cd->credential->issuer_attribute)+1;
 520     cred[i].issuer_attribute = cd->credential->issuer_attribute;
 521     cred[i].expiration = cd->credential->expiration;
 522     cred[i].signature = cd->credential->signature;
 523     cd = cd->next;
 524   }
 525   size = GNUNET_CREDENTIAL_delegation_chain_get_size (vrh->delegation_chain_size,
 526                                                       dd,
 527                                                       vrh->cred_chain_size,
 528                                                       cred);
 529   env = GNUNET_MQ_msg_extra (rmsg,
 530                              size,
 531                              GNUNET_MESSAGE_TYPE_CREDENTIAL_VERIFY_RESULT);
 532   //Assign id so that client can find associated request
 533   rmsg->id = vrh->request_id;
 534   rmsg->d_count = htonl (vrh->delegation_chain_size);
 535   rmsg->c_count = htonl (vrh->cred_chain_size);
 536
 537   if (0 < vrh->cred_chain_size)
 538     rmsg->cred_found = htonl (GNUNET_YES);
 539   else
 540     rmsg->cred_found = htonl (GNUNET_NO);
 541
 542   GNUNET_assert (-1 !=
 543                  GNUNET_CREDENTIAL_delegation_chain_serialize (vrh->delegation_chain_size,
 544                                                                dd,
 545                                                                vrh->cred_chain_size,
 546                                                                cred,
 547                                                                size,
 548                                                                (char*)&rmsg[1]));
 549
 550   GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq(vrh->client),
 551                   env);
 552   GNUNET_CONTAINER_DLL_remove (vrh_head, vrh_tail, vrh);
 553   cleanup_handle(vrh);
 554
 555   GNUNET_STATISTICS_update (statistics,
 556                             "Completed verifications", 1,
 557                             GNUNET_NO);
 558 }
 559
 560
 561 static void
 562 backward_resolution (void* cls,
 563                      uint32_t rd_count,
 564                      const struct GNUNET_GNSRECORD_Data *rd)
 565 {
 566
 567   struct VerifyRequestHandle *vrh;
 568   const struct GNUNET_CREDENTIAL_DelegationRecord *sets;
 569   struct CredentialRecordEntry *cred_pointer;
 570   struct DelegationSetQueueEntry *current_set;
 571   struct DelegationSetQueueEntry *ds_entry;
 572   struct DelegationSetQueueEntry *tmp_set;
 573   struct DelegationQueueEntry *dq_entry;
 574   char *expanded_attr;
 575   char *lookup_attribute;
 576   int i;
 577   int j;
 578
 579
 580   current_set = cls;
 581   current_set->lookup_request = NULL;
 582   vrh = current_set->handle;
 583   vrh->pending_lookups--;
 584   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 585               "Got %d attrs\n", rd_count);
 586
 587   // Each OR
 588   for (i=0; i < rd_count; i++)
 589   {
 590     if (GNUNET_GNSRECORD_TYPE_ATTRIBUTE != rd[i].record_type)
 591       continue;
 592
 593     sets = rd[i].data;
 594     struct GNUNET_CREDENTIAL_DelegationSet set[ntohl(sets->set_count)];
 595     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 596                 "Found new attribute delegation with %d sets. Creating new Job...\n",
 597                 ntohl (sets->set_count));
 598
 599     if (GNUNET_OK !=GNUNET_CREDENTIAL_delegation_set_deserialize (GNUNET_ntohll(sets->data_size),
 600                                                                   (const char*)&sets[1],
 601                                                                   ntohl(sets->set_count),
 602                                                                   set))
 603     {
 604       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 605                   "Failed to deserialize!\n");
 606       continue;
 607     }
 608     dq_entry = GNUNET_new (struct DelegationQueueEntry);
 609     dq_entry->required_solutions = ntohl(sets->set_count);
 610     dq_entry->parent_set = current_set;
 611     GNUNET_CONTAINER_DLL_insert (current_set->queue_entries_head,
 612                                  current_set->queue_entries_tail,
 613                                  dq_entry);
 614     // Each AND
 615     for (j=0; j<ntohl(sets->set_count); j++)
 616     {
 617       ds_entry = GNUNET_new (struct DelegationSetQueueEntry);
 618       if (NULL != current_set->attr_trailer)
 619       {
 620         if (0 == set[j].subject_attribute_len)
 621         {
 622           GNUNET_asprintf (&expanded_attr,
 623                            "%s",
 624                            current_set->attr_trailer);
 625
 626         } else {
 627           GNUNET_asprintf (&expanded_attr,
 628                            "%s.%s",
 629                            set[j].subject_attribute,
 630                            current_set->attr_trailer);
 631         }
 632         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 633                     "Expanded to %s\n", expanded_attr);
 634         ds_entry->unresolved_attribute_delegation = expanded_attr;
 635       } else {
 636         if (0 != set[j].subject_attribute_len)
 637         {
 638           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 639                       "Not Expanding %s\n", set[j].subject_attribute);
 640           ds_entry->unresolved_attribute_delegation = GNUNET_strdup (set[j].subject_attribute);
 641         }
 642       }
 643
 644       //Add a credential chain entry
 645       ds_entry->delegation_chain_entry = GNUNET_new (struct DelegationChainEntry);
 646       ds_entry->delegation_chain_entry->subject_key = set[j].subject_key;
 647       ds_entry->issuer_key = GNUNET_new (struct GNUNET_CRYPTO_EcdsaPublicKey);
 648       GNUNET_memcpy (ds_entry->issuer_key,
 649                      &set[j].subject_key,
 650                      sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey));
 651       if (0 < set[j].subject_attribute_len)
 652         ds_entry->delegation_chain_entry->subject_attribute =  GNUNET_strdup (set[j].subject_attribute);
 653       ds_entry->delegation_chain_entry->issuer_key = *current_set->issuer_key;
 654       ds_entry->delegation_chain_entry->issuer_attribute = GNUNET_strdup (current_set->lookup_attribute);
 655
 656       ds_entry->parent_queue_entry = dq_entry; //current_delegation;
 657       GNUNET_CONTAINER_DLL_insert (dq_entry->set_entries_head,
 658                                    dq_entry->set_entries_tail,
 659                                    ds_entry);
 660
 661       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 662                   "Checking for cred match\n");
 663       /**
 664        * Check if this delegation already matches one of our credentials
 665        */
 666       for(cred_pointer = vrh->cred_chain_head; cred_pointer != NULL;
 667           cred_pointer = cred_pointer->next)
 668       {
 669         if(0 != memcmp (&set->subject_key,
 670                         &cred_pointer->credential->issuer_key,
 671                         sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey)))
 672           continue;
 673         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 674                     "Checking if %s matches %s\n",
 675                     ds_entry->unresolved_attribute_delegation,
 676                     cred_pointer->credential->issuer_attribute);
 677
 678         if (0 != strcmp (ds_entry->unresolved_attribute_delegation,
 679                          cred_pointer->credential->issuer_attribute))
 680           continue;
 681
 682         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 683                     "Found issuer\n");
 684
 685         //Backtrack
 686         for (tmp_set = ds_entry;
 687              NULL != tmp_set->parent_queue_entry;
 688              tmp_set = tmp_set->parent_queue_entry->parent_set)
 689         {
 690           tmp_set->parent_queue_entry->required_solutions--;
 691           if (NULL != tmp_set->delegation_chain_entry)
 692           {
 693             vrh->delegation_chain_size++;
 694             GNUNET_CONTAINER_DLL_insert (vrh->delegation_chain_head,
 695                                          vrh->delegation_chain_tail,
 696                                          tmp_set->delegation_chain_entry);
 697           }
 698           if (0 < tmp_set->parent_queue_entry->required_solutions)
 699             break;
 700         }
 701
 702         if (NULL == tmp_set->parent_queue_entry)
 703         {
 704           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 705                       "All solutions found\n");
 706           //Found match
 707           send_lookup_response (vrh);
 708           return;
 709         }
 710         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 711                     "Not all solutions found yet.\n");
 712         continue;
 713
 714       }
 715       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 716                   "Building new lookup request from %s\n",
 717                   ds_entry->unresolved_attribute_delegation);
 718       //Continue with backward resolution
 719       char issuer_attribute_name[strlen (ds_entry->unresolved_attribute_delegation)+1];
 720       strcpy (issuer_attribute_name,
 721               ds_entry->unresolved_attribute_delegation);
 722       char *next_attr = strtok (issuer_attribute_name, ".");
 723       GNUNET_asprintf (&lookup_attribute,
 724                        "%s.gnu",
 725                        next_attr);
 726       GNUNET_asprintf (&ds_entry->lookup_attribute,
 727                        "%s",
 728                        next_attr);
 729       if (strlen (next_attr) == strlen (ds_entry->unresolved_attribute_delegation))
 730       {
 731         ds_entry->attr_trailer = NULL;
 732       } else {
 733         next_attr += strlen (next_attr) + 1;
 734         ds_entry->attr_trailer = GNUNET_strdup (next_attr);
 735       }
 736
 737       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 738                   "Looking up %s\n", ds_entry->lookup_attribute);
 739       if (NULL != ds_entry->attr_trailer)
 740         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 741                     "%s still to go...\n", ds_entry->attr_trailer);
 742
 743       vrh->pending_lookups++;
 744       ds_entry->handle = vrh;
 745       ds_entry->lookup_request = GNUNET_GNS_lookup (gns,
 746                                                     lookup_attribute,
 747                                                     ds_entry->issuer_key, //issuer_key,
 748                                                     GNUNET_GNSRECORD_TYPE_ATTRIBUTE,
 749                                                     GNUNET_GNS_LO_DEFAULT,
 750                                                     NULL, //shorten_key, always NULL
 751                                                     &backward_resolution,
 752                                                     ds_entry);
 753       GNUNET_free (lookup_attribute);
 754     }
 755   }
 756
 757   if(0 == vrh->pending_lookups)
 758   {
 759     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 760                 "We are all out of attributes...\n");
 761     send_lookup_response (vrh);
 762     return;
 763
 764   }
 765 }
 766
 767
 768 /**
 769  * Result from GNS lookup.
 770  *
 771  * @param cls the closure (our client lookup handle)
 772  * @param rd_count the number of records in @a rd
 773  * @param rd the record data
 774  */
 775 static void
 776 delegation_chain_resolution_start (void* cls)
 777 {
 778   struct VerifyRequestHandle *vrh = cls;
 779   struct DelegationSetQueueEntry *ds_entry;
 780   struct CredentialRecordEntry *cr_entry;
 781   vrh->lookup_request = NULL;
 782
 783   if (0 == vrh->cred_chain_size)
 784   {
 785     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 786                 "No credentials found\n");
 787     send_lookup_response (vrh);
 788     return;
 789   }
 790
 791   for (cr_entry = vrh->cred_chain_head; cr_entry != NULL; cr_entry = cr_entry->next)
 792   {
 793     if (0 != memcmp (&cr_entry->credential->issuer_key,
 794                      &vrh->issuer_key,
 795                      sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)))
 796       continue;
 797     if (0 != strcmp (cr_entry->credential->issuer_attribute, vrh->issuer_attribute))
 798       continue;
 799     //Found match prematurely
 800     send_lookup_response (vrh);
 801     return;
 802
 803   }
 804
 805   /**
 806    * Check for attributes from the issuer and follow the chain
 807    * till you get the required subject's attributes
 808    */
 809   char issuer_attribute_name[strlen (vrh->issuer_attribute)];
 810   strcpy (issuer_attribute_name,
 811           vrh->issuer_attribute);
 812   strcpy (issuer_attribute_name + strlen (vrh->issuer_attribute),
 813           ".gnu");
 814   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 815               "Looking up %s\n", issuer_attribute_name);
 816   ds_entry = GNUNET_new (struct DelegationSetQueueEntry);
 817   ds_entry->issuer_key = GNUNET_new (struct GNUNET_CRYPTO_EcdsaPublicKey);
 818   memcpy (ds_entry->issuer_key,
 819           &vrh->issuer_key,
 820           sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey));
 821   ds_entry->issuer_attribute = GNUNET_strdup (vrh->issuer_attribute);
 822   ds_entry->handle = vrh;
 823   ds_entry->lookup_attribute = GNUNET_strdup (vrh->issuer_attribute);
 824   vrh->root_set = ds_entry;
 825   vrh->pending_lookups = 1;
 826   //Start with backward resolution
 827   ds_entry->lookup_request = GNUNET_GNS_lookup (gns,
 828                                                 issuer_attribute_name,
 829                                                 &vrh->issuer_key, //issuer_key,
 830                                                 GNUNET_GNSRECORD_TYPE_ATTRIBUTE,
 831                                                 GNUNET_GNS_LO_DEFAULT,
 832                                                 NULL, //shorten_key, always NULL
 833                                                 &backward_resolution,
 834                                                 ds_entry);
 835 }
 836
 837 /**
 838  * Checks a #GNUNET_MESSAGE_TYPE_CREDENTIAL_VERIFY message
 839  *
 840  * @param cls client sending the message
 841  * @param v_msg message of type `struct VerifyMessage`
 842  * @return #GNUNET_OK if @a v_msg is well-formed
 843  */
 844 static int
 845 check_verify (void *cls,
 846               const struct VerifyMessage *v_msg)
 847 {
 848   size_t msg_size;
 849   const char* attr;
 850
 851   msg_size = ntohs (v_msg->header.size);
 852   if (msg_size < sizeof (struct VerifyMessage))
 853   {
 854     GNUNET_break (0);
 855     return GNUNET_SYSERR;
 856   }
 857   if (ntohs (v_msg->issuer_attribute_len) > GNUNET_CREDENTIAL_MAX_LENGTH)
 858   {
 859     GNUNET_break (0);
 860     return GNUNET_SYSERR;
 861   }
 862   attr = (const char *) &v_msg[1];
 863
 864   if ( strlen (attr) > GNUNET_CREDENTIAL_MAX_LENGTH)
 865   {
 866     GNUNET_break (0);
 867     return GNUNET_SYSERR;
 868   }
 869   return GNUNET_OK;
 870 }
 871
 872 /**
 873  * Handle Credential verification requests from client
 874  *
 875  * @param cls the closure
 876  * @param client the client
 877  * @param message the message
 878  */
 879 static void
 880 handle_verify (void *cls,
 881                const struct VerifyMessage *v_msg)
 882 {
 883   struct VerifyRequestHandle *vrh;
 884   struct GNUNET_SERVICE_Client *client = cls;
 885   struct CredentialRecordEntry *cr_entry;
 886   uint32_t credentials_count;
 887   uint32_t credential_data_size;
 888   int i;
 889   char attr[GNUNET_CREDENTIAL_MAX_LENGTH + 1];
 890   char issuer_attribute[GNUNET_CREDENTIAL_MAX_LENGTH + 1];
 891   char *attrptr = attr;
 892   char *credential_data;
 893   const char *utf_in;
 894
 895   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 896               "Received VERIFY message\n");
 897   utf_in = (const char *) &v_msg[1];
 898   GNUNET_STRINGS_utf8_tolower (utf_in, attrptr);
 899   GNUNET_memcpy (issuer_attribute, attr, ntohs (v_msg->issuer_attribute_len));
 900   issuer_attribute[ntohs (v_msg->issuer_attribute_len)] = '\0';
 901   vrh = GNUNET_new (struct VerifyRequestHandle);
 902   GNUNET_CONTAINER_DLL_insert (vrh_head, vrh_tail, vrh);
 903   vrh->client = client;
 904   vrh->request_id = v_msg->id;
 905   vrh->issuer_key = v_msg->issuer_key;
 906   vrh->subject_key = v_msg->subject_key;
 907   vrh->issuer_attribute = GNUNET_strdup (issuer_attribute);
 908   if (NULL == issuer_attribute)
 909   {
 910     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 911                 "No issuer attribute provided!\n");
 912     send_lookup_response (vrh);
 913     return;
 914   }
 915   /**
 916    * First, collect credentials
 917    * TODO: cleanup!
 918    */
 919   credentials_count = ntohl(v_msg->c_count);
 920   credential_data_size = ntohs (v_msg->header.size)
 921     - sizeof (struct VerifyMessage)
 922     - ntohs (v_msg->issuer_attribute_len)
 923     - 1;
 924   struct GNUNET_CREDENTIAL_Credential credentials[credentials_count];
 925   credential_data = (char*)&v_msg[1] + ntohs (v_msg->issuer_attribute_len) + 1;
 926   if (GNUNET_OK != GNUNET_CREDENTIAL_credentials_deserialize (credential_data_size,
 927                                                               credential_data,
 928                                                               credentials_count,
 929                                                               credentials))
 930   {
 931     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 932                 "Cannot deserialize credentials!\n");
 933     send_lookup_response (vrh);
 934     return;
 935   }
 936
 937   for (i=0;i<credentials_count;i++) {
 938     cr_entry = GNUNET_new (struct CredentialRecordEntry);
 939     cr_entry->credential = GNUNET_malloc (sizeof (struct GNUNET_CREDENTIAL_Credential) +
 940                                           strlen (credentials[i].issuer_attribute) + 1);
 941     GNUNET_memcpy (cr_entry->credential,
 942                    &credentials[i],
 943                    sizeof (struct GNUNET_CREDENTIAL_Credential));
 944     GNUNET_memcpy (&cr_entry->credential[1],
 945                    credentials[i].issuer_attribute,
 946                    strlen (credentials[i].issuer_attribute));
 947     cr_entry->credential->issuer_attribute = (char*)&cr_entry->credential[1];
 948     GNUNET_CONTAINER_DLL_insert_tail (vrh->cred_chain_head,
 949                                       vrh->cred_chain_tail,
 950                                       cr_entry);
 951     vrh->cred_chain_size++;
 952   }
 953
 954   delegation_chain_resolution_start (vrh);
 955
 956 }
 957
 958 /**
 959  * We encountered an error while collecting
 960  */
 961 static void
 962 handle_cred_collection_error_cb (void *cls)
 963 {
 964   struct VerifyRequestHandle *vrh = cls;
 965   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 966               "Got disconnected from namestore database.\n");
 967   vrh->cred_collection_iter = NULL;
 968   send_lookup_response (vrh);
 969 }
 970
 971 static void
 972 collect_next (void *cls)
 973 {
 974   struct VerifyRequestHandle *vrh = cls;
 975   vrh->collect_next_task = NULL;
 976   GNUNET_assert (NULL != vrh->cred_collection_iter);
 977   GNUNET_NAMESTORE_zone_iterator_next (vrh->cred_collection_iter);
 978 }
 979
 980 /**
 981  * Store credential
 982  */
 983 static void
 984 handle_cred_collection_cb (void *cls,
 985                            const struct GNUNET_CRYPTO_EcdsaPrivateKey *key,
 986                            const char *label,
 987                            unsigned int rd_count,
 988                            const struct GNUNET_GNSRECORD_Data *rd)
 989 {
 990   struct VerifyRequestHandle *vrh = cls;
 991   struct GNUNET_CREDENTIAL_Credential *crd;
 992   struct CredentialRecordEntry *cr_entry;
 993   int cred_record_count;
 994   int i;
 995
 996   cred_record_count = 0;
 997   for (i=0; i < rd_count; i++)
 998   {
 999     if (GNUNET_GNSRECORD_TYPE_CREDENTIAL != rd[i].record_type)
1000       continue;
1001     cred_record_count++;
1002     crd = GNUNET_CREDENTIAL_credential_deserialize (rd[i].data,
1003                                                     rd[i].data_size);
1004     if (NULL == crd)
1005     {
1006       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1007                   "Invalid credential found\n");
1008       continue;
1009     }
1010     cr_entry = GNUNET_new (struct CredentialRecordEntry);
1011     cr_entry->credential = crd;
1012     GNUNET_CONTAINER_DLL_insert_tail (vrh->cred_chain_head,
1013                                       vrh->cred_chain_tail,
1014                                       cr_entry);
1015     vrh->cred_chain_size++;
1016   }
1017   vrh->collect_next_task = GNUNET_SCHEDULER_add_now (&collect_next,
1018                                                      vrh);
1019 }
1020
1021 /**
1022  * We encountered an error while collecting
1023  */
1024 static void
1025 handle_cred_collection_finished_cb (void *cls)
1026 {
1027   struct VerifyRequestHandle *vrh = cls;
1028   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1029               "Done collecting credentials.\n");
1030   vrh->cred_collection_iter = NULL;
1031   delegation_chain_resolution_start (vrh);
1032 }
1033
1034 /**
1035  * Handle Credential collection requests from client
1036  *
1037  * @param cls the closure
1038  * @param client the client
1039  * @param message the message
1040  */
1041 static void
1042 handle_collect (void *cls,
1043                 const struct CollectMessage *c_msg)
1044 {
1045   char attr[GNUNET_CREDENTIAL_MAX_LENGTH + 1];
1046   char issuer_attribute[GNUNET_CREDENTIAL_MAX_LENGTH + 1];
1047   struct VerifyRequestHandle *vrh;
1048   struct GNUNET_SERVICE_Client *client = cls;
1049   char *attrptr = attr;
1050   const char *utf_in;
1051
1052   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1053               "Received COLLECT message\n");
1054
1055   utf_in = (const char *) &c_msg[1];
1056   GNUNET_STRINGS_utf8_tolower (utf_in, attrptr);
1057
1058   GNUNET_memcpy (issuer_attribute, attr, ntohs (c_msg->issuer_attribute_len));
1059   issuer_attribute[ntohs (c_msg->issuer_attribute_len)] = '\0';
1060   vrh = GNUNET_new (struct VerifyRequestHandle);
1061   GNUNET_CONTAINER_DLL_insert (vrh_head, vrh_tail, vrh);
1062   vrh->client = client;
1063   vrh->request_id = c_msg->id;
1064   vrh->issuer_key = c_msg->issuer_key;
1065   GNUNET_CRYPTO_ecdsa_key_get_public (&c_msg->subject_key,
1066                                       &vrh->subject_key);
1067   vrh->issuer_attribute = GNUNET_strdup (issuer_attribute);
1068
1069   if (NULL == issuer_attribute)
1070   {
1071     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1072                 "No issuer attribute provided!\n");
1073     send_lookup_response (vrh);
1074     return;
1075   }
1076   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1077               "Getting credentials for subject\n");
1078   /**
1079    * First, get attribute from subject
1080    */
1081   vrh->cred_collection_iter = GNUNET_NAMESTORE_zone_iteration_start (namestore,
1082                                                                      &c_msg->subject_key,
1083                                                                      &handle_cred_collection_error_cb,
1084                                                                      vrh,
1085                                                                      &handle_cred_collection_cb,
1086                                                                      vrh,
1087                                                                      &handle_cred_collection_finished_cb,
1088                                                                      vrh);
1089 }
1090
1091
1092 /**
1093  * Checks a #GNUNET_MESSAGE_TYPE_CREDENTIAL_COLLECT message
1094  *
1095  * @param cls client sending the message
1096  * @param v_msg message of type `struct CollectMessage`
1097  * @return #GNUNET_OK if @a v_msg is well-formed
1098  */
1099 static int
1100 check_collect (void *cls,
1101                const struct CollectMessage *c_msg)
1102 {
1103   size_t msg_size;
1104   const char* attr;
1105
1106   msg_size = ntohs (c_msg->header.size);
1107   if (msg_size < sizeof (struct CollectMessage))
1108   {
1109     GNUNET_break (0);
1110     return GNUNET_SYSERR;
1111   }
1112   if (ntohs (c_msg->issuer_attribute_len) > GNUNET_CREDENTIAL_MAX_LENGTH)
1113   {
1114     GNUNET_break (0);
1115     return GNUNET_SYSERR;
1116   }
1117   attr = (const char *) &c_msg[1];
1118
1119   if ( ('\0' != attr[ntohs(c_msg->header.size) - sizeof (struct CollectMessage) - 1]) ||
1120        (strlen (attr) > GNUNET_CREDENTIAL_MAX_LENGTH) )
1121   {
1122     GNUNET_break (0);
1123     return GNUNET_SYSERR;
1124   }
1125   return GNUNET_OK;
1126 }
1127
1128 /**
1129  * One of our clients disconnected, clean up after it.
1130  *
1131  * @param cls NULL
1132  * @param client the client that disconnected
1133  */
1134 static void
1135 client_disconnect_cb (void *cls,
1136                       struct GNUNET_SERVICE_Client *client,
1137                       void *app_ctx)
1138 {
1139   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1140               "Client %p disconnected\n",
1141               client);
1142 }
1143
1144 /**
1145  * Add a client to our list of active clients.
1146  *
1147  * @param cls NULL
1148  * @param client client to add
1149  * @param mq message queue for @a client
1150  * @return this client
1151  */
1152 static void *
1153 client_connect_cb (void *cls,
1154                    struct GNUNET_SERVICE_Client *client,
1155                    struct GNUNET_MQ_Handle *mq)
1156 {
1157   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1158               "Client %p connected\n",
1159               client);
1160   return client;
1161 }
1162
1163 /**
1164  * Process Credential requests.
1165  *
1166  * @param cls closure
1167  * @param server the initialized server
1168  * @param c configuration to use
1169  */
1170 static void
1171 run (void *cls,
1172      const struct GNUNET_CONFIGURATION_Handle *c,
1173      struct GNUNET_SERVICE_Handle *handle)
1174 {
1175
1176   gns = GNUNET_GNS_connect (c);
1177   if (NULL == gns)
1178   {
1179     fprintf (stderr,
1180              _("Failed to connect to GNS\n"));
1181   }
1182   namestore = GNUNET_NAMESTORE_connect (c);
1183   if (NULL == namestore)
1184   {
1185     fprintf (stderr,
1186              _("Failed to connect to namestore\n"));
1187   }
1188
1189   statistics = GNUNET_STATISTICS_create ("credential", c);
1190   GNUNET_SCHEDULER_add_shutdown (&shutdown_task, NULL);
1191 }
1192
1193
1194 /**
1195  * Define "main" method using service macro
1196  */
1197 GNUNET_SERVICE_MAIN
1198 ("credential",
1199  GNUNET_SERVICE_OPTION_NONE,
1200  &run,
1201  &client_connect_cb,
1202  &client_disconnect_cb,
1203  NULL,
1204  GNUNET_MQ_hd_var_size (verify,
1205                         GNUNET_MESSAGE_TYPE_CREDENTIAL_VERIFY,
1206                         struct VerifyMessage,
1207                         NULL),
1208  GNUNET_MQ_hd_var_size (collect,
1209                         GNUNET_MESSAGE_TYPE_CREDENTIAL_COLLECT,
1210                         struct CollectMessage,
1211                         NULL),
1212  GNUNET_MQ_handler_end());
1213
1214 /* end of gnunet-service-credential.c */